Hair treating devices, especially for curling hair, are well known in the form of "rollers" which are typically cylindrical mandrels or bobbins of such size that a hank of hair may be wound thereon for shaping and drying purposes. Such rollers have been fabricated in a wide variety of shapes, sizes and materials and have been widely used for both professional and in-the-home hair treatment. Since the advent of such devices, means have been sought for accelerating the drying of wet hair on the rollers and for obtaining a curl having enhanced characteristics of softness and permanence. The acceleration of drying with hair rollers has been accomplished by apparatus which forces heated air over the roller supported hair, usually with the aid of an air circulating bonnet. This forced air bonnet apparatus is known to be undesirably confining and uncomfortable for the user. In the professional hair salon the person receiving the hair treatment is usually seated under a dryer until the desired degree of dryness is achieved. In the home treatment, a portable hair dryer is commonly used which requires a connection to the electrical outlet to energize the portable heater and blower and hence the person is confined to a small area of movement.
There has been much effort by others to provide means for accelerating hair drying on rollers without a forced air bonnet to thereby allow the user complete freedom of movement during the drying period. It has been proposed, for example, to incorporate exothermic materials into hair rollers so that wetting of the material produces a reaction which generates heat and accelerates drying of the hair. Such devices are disclosed, for example, in the U.S. Pat. No. 2,074,816 granted Mar. 23, 1937 to Trotter, and U.S. Pat. No. 2,630,809 granted Mar. 10, 1953 to Lewis et al. Exothermic rollers have not gained significant acceptance, presumably because of the difficulty in controlling the temperature of the device.
Another prior art approach to accelerated hair drying is represented by preheated rollers. Such devices usually are provided with a heat retaining member inside the roller and heat is stored in the member prior to use. The heat may be put into the roller by immersing the same into heated liquid or by so-called dry heat from electrical heaters. A preheated roller for simultaneously drying and curling is disclosed in U.S. Pat. No. 3,705,974 granted Dec. 12, 1972 to Nilsson. Another example of a preheated roller is shown in U.S. Pat. No. 3,485,248 granted Dec. 23, 1969 to Murrey et al. In this patent a cylindrical roller comprises a plastic shell which is filled with a thermoplastic composition as a heat storage medium. It has been proposed also, in the prior art, to add powdered metal for heat storage purposes to pellets of absorbent silicates mixed with clay contained in a hair drying roller. This is disclosed in U.S. Pat. No. 3,656,490 granted Apr. 18, 1972 to Grossman. Such preheated rollers function primarily to drive the water from the hair directly into the surrounding air in the form of water vapor. This process causes drying to proceed at a rate determined largely by the roller temperature and the embient conditions. Consequently, the results achieved are not consistent from time to time, even with a given user. Preheated rollers, known as "hot rollers", have been used extensively in recent years for setting of dry hair. Such rollers are not intended for drying wet hair. An example of a hot roller is disclosed in U.S. Pat. No. 3,541,302 granted Nov. 17, 1970 to Makino.
Th use of desiccant in a hair roller has been proposed for the purpose of accelerating the drying. It is known, for example to construct a roller with a tubular body and fill the central passage of the body with a loose granular desiccant. Such an arrangement is shown in the U.S. Pat. No. 3,431,917 granted to M. F. Harris on Mar. 11, 1969. It is also known in the prior art to provide a spool shaped roller body and fill the annular space between the spool flanges with desiccant, as disclosed in the U.S. patent Reissue No. 27,033 granted Jan. 19, 1971 to H. Mitsumoto. The use of desiccant in powder or particle form poses a problem in containment thereof, and it is believed that this is one reason that such devices have not gained commercial acceptance. Certain of the prior art disclosures of desiccant type rollers describe a desiccant body comprised of powder or particles of desiccant which are somehow held together to form a selfsustaining body. This arrangement is disclosed in the U.S. Pat. No. 2,646,053 granted to M. F. Harris on July 21, 1953 and in U.S. Pat. No. 3,175,562 granted to C. F. Reed on Mar. 30, 1965. Also such a structure is alluded to in the above-cited Mitsumoto patent. Molded desiccant bodies, as heretofore proposed, have not gained acceptance, presumably because the prior art techniques for binding desiccant granules resulted in ineffective or inefficient structures for acceleration of the hair drying process.